Sister Bay Waterworks, WI
Lead detected, under the action levels
Latest 90th-percentile lead: 6.1 ppb (monitoring period 2023-2023). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Lead was measured in sampled homes but the 90th percentile is under both action levels. EPA's health goal for lead is zero, so test your own tap if your home was built before 1986 or anyone in it is pregnant or a young child.
Sister Bay Waterworks at a glance
Sister Bay Waterworks serves about 1,000 people through 1,507 service connections, which makes it a small system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Door County, Wisconsin. EPA system ID: WI4150510. Ask the utility on your bill for your address in their service line inventory.
Every lead result on file
That is up 2.6 ppb from 3.5 ppb in the period ending 2020. The highest 90th-percentile result EPA holds for Sister Bay Waterworks is 9.7 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 6.1 ppb |
| 2020 | 3.5 ppb |
| 2017 | 9.7 ppb |
Where this result ranks
Of the 947 Wisconsin systems with a lead result, the median latest reading is 1.33 ppb; 6 are over 15 ppb right now and 71 have gone over at some point. Sister Bay Waterworks's 6.1 ppb sits at the 91st percentile in Wisconsin and the 94th nationally (higher means more lead).
Neighbouring systems
5 other systems share Door County; 1 of them has a higher latest lead result than Sister Bay Waterworks. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Sturgeon Bay Waterworks | 9,700 | 3.6 ppb |
| Oaks The | 135 | 0.95 ppb |
| Heritage Lake Resort | 130 | 13 ppb |
| Maplewood Sanitary Dist 1 | 122 | 0.21 ppb |
| Cottage Glen Condominiums | 52 | 1.25 ppb |
Next steps for Sister Bay, WI
Test your own tap with a certified lab first-draw sample; Sister Bay, WI may offer free or low-cost kits through the utility. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Sister Bay Waterworks whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. Why sampled homes are the worst-case ones is in the guide to reading the number. Systems that went over once often dip back under; here is what that means.